writes "Tech bubbles happen, writes BW's Ashlee Vance, but we usually gain from the innovation left behind. But this one — driven by social networking — could leave us empty-handed. Math whiz Jeff Hammerbacher provides a good case study. One year out of Harvard, 23-year-old Hammerbacher arrived at Facebook, was given the lofty title of research scientist and put to work analyzing how people used the social networking service. Over the next two years, Hammerbacher assembled a team that built a new class of analytical technology, one which translated insights into people's relationships, tendencies, and desires into precision advertising and higher sales. But something gnawed at him. Hammerbacher looked around Silicon Valley at companies like his own, Google, and Twitter, and saw his peers wasting their talents. 'The best minds of my generation are thinking about how to make people click ads,' he says. 'That sucks.' Silicon Valley historian Christophe Lecuyer agrees: 'It's clear that the new industry that is building around Internet advertising and these other services doesn't create that many jobs. The loss of manufacturing and design knowhow is truly worrisome.'"